The bike runs great as long as i don´t connect the battery, and yes i know its a 6VDC system. The batt is new and charged. when i connect the battery it runs great for about 5 minutes then starts to miss and backfire. If i let it sit (not running) for 20 min. it runs good for a few min. then starts doing same. If i disconnect the batt. (after the cool down period)it runs fine. Something is getting hot (electrically) coil, exciter coil, voltage regulator (i´m not sure if it has one, cannot locate it.